Fascinating story at http://www.news.cornell.edu/stories/Sept12/SimpleLanguage.html that seems be a vindication of the pattern-matching approach to chatbot development.
The original article is here:
http://rspb.royalsocietypublishing.org/content/early/2012/09/05/rspb.2012.1741.full
Our hypothesis has potential implications for the subareas of computer science dealing with human language. Specifically, it suggests that more human-like speech and language processing may be accomplished by focusing less on hierarchical structure and dealing more with sequential structure. Indeed, in the field of Natural Language Processing, the importance of sequential processing is increasingly recognized: tasks such as machine translation and speech recognition are successfully performed by algorithms based on sequential structure. No significant performance increase is gained when these algorithms are based on or extended with hierarchical structure